5:4 Although the Kryptonian alphabet used here doesn't seem to match any available translations, you can learn more about the language at the "Superman through the Ages" Encyclopaedia website.
The animal shown here is a Thought-Beast, one of many absurd animals native to Krypton. The screen on its head displays its thoughts.

7:6 Rao was a deity worshipped by Kryptonians. In author Alan Moore's classic story "For the Man Who Has Everything" (Superman Annual #11, published in the same year), Superman hallucinates about his father being a member of a revolutionary group called the Sword of Rao.

9:1-3 Coast City was the Green Lantern's home. Central City was the base of operations for the Flash. Star City was the Green Arrow's stomping grounds.
The faces pictured are (from left to right) the Flash, Wonder Woman, Lana Lang, Batman and Jimmy Olsen.

9:4 "Cal Ellis" is a play on Superman's Krypytonian name: Kal El.Note the "super" sale sign.

10:4 Kara is Superman's cousin, Supergirl.

COMMENT: This story was published before the complete revision of DC Comics' continuity called "Crisis on Infiinite Earths". Swamp Thng witnessed the event in ST 46 . After the Crisis many aspects of the Superman mythos had changed, including the level of his powers and his knowledge of Krypton. In a story published three years later, Swamp Thing meets Superman in SWAMP THING 79, but their meeting in this issue is not mentioned. Superman's first meeting with Swamp Thing was in DC PRESENTS #8 (cover at right).